DOI: 10.1111/tog.12064 2014;16:29–36 Review The Obstetrician & Gynaecologist http://onlinetog.org Nerve injuries associated with gynaecological surgery a b, a Olayemi Kuponiyi MRCOG, Djavid I Alleemudder MRCOG MRCS(Ed) BSc, * Adeyinka Latunde-Dada BMBS BMedSci, c Padma Eedarapalli MD MRCOG aSpecialist Trainee, Queen Alexandra Hospital, Southwick Hill Road, Cosham, Portsmouth PO6 3LY, UK. bSpecialist Trainee, Salisbury NHS Trust, Odstock Road, Salisbury SP2 8BJ, UK. cConsultant Obstetrician & Gynaecologist, Royal Bournemouth Hospital, Castle Lane East, Bournemouth BH7 7DW, UK *Correspondence: Djavid Alleemudder. Email: [email protected] Accepted on 24 September 2013 Key content Learning objectives Nerve injuries are a common complication of gynaecological To gain an overview of the spectrum of different neuropathies that surgery, occurring in 1.1–1.9% of cases. may occur following pelvic surgery. Patient mal-positioning, incorrect placement of self-retaining To learn about safe surgical techniques in the prevention of retractors, haematoma formation and direct nerve entrapment or postoperative neuropathies. transection are the primary causative factors in perioperative To review the clinical anatomy of the lumbo-sacral and nerve injury. brachial plexuses. Nerves most commonly injured during surgery include the Ethical issues femoral, ilioinguinal, pudendal, obturator, lateral cutaneous, Neuropathies can cause considerable postoperative morbidity. iliohypogastric and genitofemoral nerves. Should neuropathies following gynaecology surgery be discussed The majority of neuropathies resolve with conservative routinely during consent taking? management and physiotherapy. Neuropathies following surgery may have considerable Selective serotonin reuptake inhibitors (SSRIs), tricyclic medico-legal implications. antidepressants and gamma-aminobutyric acid (GABA) antagonists are of significant benefit in managing Keywords: gynaecological surgery / nerve injury / neuropathy painful neuropathies. Please cite this paper as: Kuponiyi O, Alleemudder DI, Latunde-Dada A, Eedarapalli P. Nerve injuries associated with gynaecological surgery. The Obstetrician & Gynaecologist 2014;16:29–36. Introduction and parasympathetic injuries to the nervous supply of the bladder and bowel are beyond the scope of this article. Iatrogenic nerve injury following gynaecological surgery occurs more commonly than is recognised and is a Pathophysiology of nerve injury significant cause of postoperative neuropathy. Patient mal-positioning, improper incision sites and self-retaining Neuropathy results when there is a disruption to the blood retractors are major contributors to the origins of supply of the nerve caused by injury. Three types of intraoperative gynaecological nerve injury. microvascular changes occur with nerve injury (Table 1). The incidence of neuropathy following gynaecological Neuropraxia is the result of external nerve compression – surgery is between 1.1 and 1.9%.1 3 The majority of cases leading to a disruption of conduction across a small portion will have a good prognosis, with minimal or no of the axon. Nerve recovery takes weeks or months once intervention necessary for resolution of the neurological remyelination occurs. impairment. A minority of patients sustain long-term Axonotmesis is caused by profound nerve compression or complications necessitating prolonged treatment or even traction. Damage occurs to the axon only, with preservation reparative surgery. of the supporting Schwann cells. Regeneration is possible In this article the authors outline the anatomy of the because supporting Schwann cells remain intact. Recovery susceptible nerves, describe the common mechanisms of time is longer than neuropraxia. injury and discuss the management of such injuries. The The most severe form of injury is termed neurotmesis, and preventative strategies to reduce neuropathies and the it results from complete nerve transection or ligation, where medico-legal ramifications are also discussed. Sympathetic both the axon and Schwann cells are disrupted. Regeneration ª 2014 Royal College of Obstetricians and Gynaecologists 29 Nerve injuries associated with gynaecological surgery Table 1. Pathophysiology of nerve injury Type of nerve injury Pathophysiology Prognosis Neuropraxia External nerve compression Recovery within weeks to months Axonotmesis Severe compression with axon damage Recovery takes longer usually several months Neurotmesis Nerve transection with damage to Schwann cells Poor prognosis without restorative surgery is rendered impossible and without restorative surgery, Entrapment nerve injuries are more commonly prognosis is usually poor.2,4 encountered in pelvic floor reconstruction surgery. Pain is a common symptom of nerve entrapment in contrast to loss Mechanism of nerve injury of function and numbness that occurs with nerve transection. A recent study showed that chronic nerve-related pain was The mechanism of intraoperative nerve injury involves a seen in 7% of women following Pfannenstiel incisions and combination of compression, stretch, entrapment or this was attributed to entrapment of the ilioinguinal and transection of nerve fibres.3 iliohypogastric nerves.8 Compression and stretch injuries are typically caused by Although rare, another source of perioperative improper placement of self-retaining retractors such as the lumbosacral nerve injury to consider is related to Balfour or Brookwalter retractors5,6 and in prolonged complications of regional anaesthesia. During epidural or positioning of the patient in stirrups. spinal neuraxial blockade, poor technique may cause Transection injuries are largely related to incorrectly sited paraesthesia and pain as a result of needle or catheter tip surgical incisions. The Pfannenstiel and low transverse trauma to nerve roots and the spinal cord. Pain may also incisions are the most common incisions performed in result from injection of anaesthetic into the wrong spinal gynaecology. Should these incisions extend beyond the compartment. Most often, neurological damage secondary lateral margin of the inferior rectus abdominus muscle, the to regional anaesthesia administration is immediately lateral cutaneous branches of the iliohypogastric and apparent as the patient becomes symptomatic during ilioinguinal nerves are liable to be injured (Figure 1). A the procedure.9,10 cadaver study found that abdominal wall incisions below the level of the anterior superior iliac spine and Specific nerve anatomy and related approximately 5 cm superior to the pubic symphysis had neuropathies the greatest potential for injuring the ilioinguinal or iliohypogastric nerves.7 The nerves most commonly injured during pelvic surgery originate from the lumbosacral and brachial plexuses (Figures 2 and 3). Table 2 provides a summary of the nerve components of the lumbosacral plexus, their function and clinical presentation after injury. Femoral nerve The femoral nerve originates from nerve roots L2–L4. It passes infero-laterally through the psoas muscle and emerges from its lateral border. It exits the pelvis beneath the inguinal ligament, lateral to the femoral vessels to enter the thigh. Gynaecological surgery is the most common contributor to iatrogenic femoral nerve injury, and abdominal hysterectomy is mostly responsible for this.11 Of all reports of gynaecological associated neuropathy, the femoral nerve is most frequently implicated, with an incidence of at least 11%.12 Femoral neuropathy commonly occurs as a result of compression of the nerve against the pelvic sidewall as it Figure 1. Ilioinguinal and iliohypogastric nerves in relation to lower emerges from the lateral border of the psoas muscle. This transverse abdominal incision. happens when excessively deep retractor blades are used or 30 ª 2014 Royal College of Obstetricians and Gynaecologists Kuponiyi et al. of the hip results in kinking of the femoral nerve under the inguinal ligament.13 Femoral neuropathy presents with weakness of hip flexion and adduction and knee extension. There is loss of the knee jerk reflex and paraesthesia over the anterior and medial thigh, as well as the medial aspect of the calf. Ilioinguinal and iliohypogastric nerves The T12–L1 nerve root gives rise to the ilioinguinal and iliohypogastric nerves. Both nerves pass laterally through the head of the psoas muscle before running diagonally along quadratus lumborum. The iliohypogastric nerve pierces the external oblique aponeurosis above the superficial inguinal ring, while the ilioinguinal nerve emerges through it. Both nerves have a sensory function only. While the Iliohypogastric provides sensation to the skin of the gluteal Figure 2. Lumbosacral plexus. Reproduced with permission from and hypogastric regions, the ilioinguinal nerve provides Gray JE. Nerve injury associated with pelvic surgery. In: UpToDate, sensory innervation to the skin overlying the groin, inner Basow DS (Ed), UpToDate, Waltham, MA 2013. Copyright thigh and labia majora. ª UpToDate, Inc. For more information visit www.uptodate.com. Injury to these nerves is typically caused by suture entrapment at the lateral borders of low transverse or Pfannenstiel incisions that extend beyond the lateral border of the rectus abdominus muscle. The reported incidence of ilioinguinal or iliohypogastric neuropathy following a Pfannenstiel incision is 3.7%.15 Laparoscopic and retropubic mid urethral tape procedures may also injure this nerve.16 The diagnostic triad for ilioinguinal/iliohypogastric nerve entrapment